In the oil refining and chemical industry, high temperature centrifugal pumps play an important role in rotating machines, and their cooling or heating is still the focus of attention in this field.
Most of the methods so far focus on cooling the stationary parts of the centrifugal pump, such as the bearing housing, mechanical sealing gland, etc., which are shown in the Chapter “Cooling Water and Lubrication System” of API610 Appendix B (Standard) and the Chapter “Standard Flushing Solution and Standard Seal Flush Solution 02 in Auxiliary Metal Components” of API682 Appendix D (Standard Appendix); and even the methods for the cooling of the rotating parts are also limited to the cooling of the local surface, as described in the Chapter “Standard Flushing Solution and Standard Seal Flush Solution in Auxiliary Metal Components 51, 61, 65A, 65B, 66A, 66B and 52, 53A, 53B, 53C, 54, 55” of API 682 Appendix D (Standard Appendix). Furthermore, the cooling fluid neither can rotate simultaneously together with the rotating part nor can flow along the axial direction after the cooling fluid is in contact with partial rotating part, and the flow area is small. As shown in FIG. 1 and FIG. 2, the cooling channel is formed on the sealing gland 5 of each side of the cantilevered centrifugal pump, i.e., cooling or heating fluid can only be circulated in the channel located on the sealing gland 5 of each side of the cantilevered centrifugal pump, whereas the pump shaft 7 can not be cooled or heated.
In addition, the methods of cooling the stationary component of the centrifugal pump body in the exemplary embodiment is: introduce low temperature circulating fluid, e.g., water, oil, steam or nitrogen, into the pump chamber, bearing box and the hollow cavity of mechanical sealing gland; the fluid flows through the stationary high-temperature parts and then flows out with removing the heat, and the output fluid becomes a high-temperature fluid, and then the fluid flows through the stationary cooler arranged outside the pump for cooling down the temperature, and then reintroduces the low-temperature fluid into the stationary components of pump for circulation, and thus achieves the purpose of controlling the temperature of the pump. This method is called cooling.
Similarly, when the pump needs to be heated, replace the cooler in the above-mentioned cooling method with heater to achieve a heating method. Heating in this way is called heating.
Until now, there is no such technology as introducing the fluid directly into the hollow cavity of rotating parts of the high-temperature centrifugal pump for continuous rotation to achieve cooling or heating.
Thus, the deficiencies in prior art for cooling or heating the high temperature centrifugal pumps are:
(A) only performing cooling or heating to the surface of the rotating parts (such as: shaft or sleeve) of high temperature centrifugal pump has the deficiencies of:
1. The cooling fluid only contacts partial surface of the rotating parts of the centrifugal pump, i.e., the axial length of fluid contacting the rotating parts is short, so that the overflowing area of cooling fluid is small;
2. The portion of the rotating part cooled or heated by the fluid is not the position where most in need of cooling or heating;
3. The fluid can not be axially displaced when it contacts with the surface of the rotating part of the centrifugal pump, so that the convection effect is poor;
4. Targeted cooling cannot be achieved to the whole rotating parts;
5. Direct contacting the cooling fluid with the pump shaft can not be achieved.
(B) Only performing cooling or heating to the stationary components of pump body, e.g. pump casing, bearing box and mechanical sealing gland, has the deficiencies of:
1. All the stationary components are in contact with the atmosphere, which temperature is not same as the core position. Therefore, the true problem of controlling the temperature of core position is not solved yet;
2. The variation of accurate temperature and transient temperature of the core position cannot be accurately measured and monitored;
3. In prior art, there is always a freshly to be transferred feeding material between the components where are cooled or heated and the core components where really need to be cooled or heated, i.e., the feeding material transfers heat to the rotor with a certain time, and the most of the fluid contacted with the rotating parts of the core components of the high temperature centrifugal pump is the freshly to be transferred feeding material. However, these feeding material are simply too late to get cooled or heated to flow away, and replaced by new fresh feeding material, and these fresh feeding material are of constant temperature subjecting to refining or chemical process, i.e., the core position of the rotating parts are always not directly cooled or heated according to the existing technology, more like a light dusting;
4. The rotating parts of the high temperature centrifugal pump are the parts that need to be cooled most, keeping them in a high temperature state will bring a lot of unfavorable factors, which are not listed herein.
5. Similarly, the rotating parts of the high temperature centrifugal pump are the parts that need to be heated most, leaving them without adequate heating will bring a serious result, especially in the startup time, which are not too much mentioned herein.